I wanted to keep the stock sound levels on my XB but I also had reasons to want some decibels every now and then. The idea of making a really cool exhaust system appealed to me. The problem is that I come and go in the wee hours and my neighbors don’t deserve to lose sleep over my need to satisfy my inner seven year old. This bike is my main commuter, which means that my main focus should be on reliability not outright horsepower. If we were talking about a car here, I’d just get a pair of electric cutouts…
That leads us to my Jegs order; I got one of their two and a half inch electric cutouts and a Y-pipe with a three bolt flange arrangement. The diagrams of the XB12 muffler and the pictures of gutted units on the net were instrumental in getting this exactly right. The desired path with the valve open was; out of the header through the first pass in the muffler which takes it back to the very rear chamber, then back to the front chamber through pass #2. The gas exit’s the cutout at that point having made two internal passes. If the valve is open and it allowed to roll past five thousand RPM, the internal valve opens and you essentially have a header and half a foot of pipe for an exhaust path. This is where things go to loud town. This will be an incredibly infrequent occasion as this is my commuter and I’m at 3K-4.5K most of the time. I’m not going to fry my valves or exploderate my motor parts with this setup in case you were concerned about back pressure. Even in it’s shortest configuration,(both valves open) it has plenty of exhaust pipe to prevent smoking an exhaust valve.
The location for the hole saw was decided upon for a number of reasons: It had to be aligned with the correct chamber to achieve the desired sound. It also couldn’t interfere with the stock chin fairing. Last of all Mik had to be able to get the Mig welder into position to weld the flange to the muffler. All of that being said, the location of the cutout is a compromise overall. The second iteration of this project will be inside the muffler or perhaps just frenched into the side offering a much lower profile. This XB however is an STT which is pretty tall and has glorious ground clearance, so I’m not worried at all.
The two and a half inch hole saw was brand new and tore right through the muffler making a very tidy hole. Three studs with six nut were used to dial in the depth and alignment settings accurately. I would not be at the welders house when this all happened so I had to make sure that this was attached to exact spot I designated.
When the muffler came back, it needed to be stripped and recoated to attack some corrosion and protect the steel better. After stripping and sanding, I used VHT Flameproof very high temperature header paint to coat the hot spots on the muffler. Those areas were; right after the header, the front nose cone, and the rear cap. Those areas were liberally coated with the VHT coating before the second coating was applied. That was Dupli-color TR-250 truck bed coating. I used this very spray coating to make black me primary cover(ARRRR). It’s super durable and seems to withstand a fairly rude amount of heat as well. Multiple light coats of both sprays were used to build up a strong shell. The cutout valve was also coated in the VHT and then coated in a 500 degree Fahrenheit clear coat meant for engine blocks. The reason for coating the cutout was that it is made of aluminum and seemed to stand out too much visually, also the soft aluminum needed something to protect it.
The wiring was easy and the harness need to be shortened because it was made to be for a car or truck. The switch needs a mount to be fabbed, but I’m going to do a little shopping to find a switch mount that’s right for the job. There will also be a cover made of thin stainless sheet to protect the cutout flange, pipe, and cutout assembly. That is a separate project with its own challenges. More to come on that chapter.
There will be some video of the bike very soon, and I’ll upload it as soon as I get it filmed. The sound with the valve open is oh so nice and satisfies me completely. I got exactly what I wanted here in terms of sound. The only thing that should change in the future is the configuration and mounting of the cutout valve.
Now the deer and turkeys will get the fork out of my way before I get to them. The option to announce my presence to an inattentive texting teen driver is very nice as well. I drive through two high schools on my way commute and find myself dodging seventeen year old girls who are multitasking in the car. I want her to know I’m there before evasive maneuvers are necessary.
Best of all, I can activate stealth mode when the time’s right.